Studies on the biosynthesis of the mitomycin antibiotics will be continued. Specifically tritium and oxygen-18 labeled D-glucosamine molecules will be synthesized and fed to Streptomyces verticillatus to investigate the formation of the aziridine ring of these antibiotics and to learn mechanistic details of some of the biochemical reactions involved in D-glucosamine utilization. In addition experiments will be carried out to probe the possible involvement of heptuloses in mitomycin biosynthesis. Degradations to afford access to specific carbon atoms of the methylbenzoquinone moiety of these antibiotics will be worked out and utilized to probe the involvement of the heptuloses and of other cabohydrates in the formation of the quinone moiety.